Yes, definitely. You don't even have to root the device. Copy it into /mnt/ext1/applications and it will show up in the Applications menu. You can build E-Ink capable applications using the SDK and install them (I recommend sergeyvl12's version of the SDK). You can also take utility programs from the Debian ARM distribution that LoneTech provided for running under qemu on a desktop system and run them on the Pro and 360+ devices. The devices also have a shell via BusyBox, and you can run scripts on them via Applications or the poterm application. You won't have root privileges (unless you run the get_root app under one of the older firmware versions), but you can do a lot without them. paola maintains a collection of useful information found in this thread: http://www.mobileread.com/forums/sho...d.php?t=119973

Are "we" able to install and run a linux program on one of these devices? Is that capability available to linux versed end users?

Yes, we are, just as previous poster said.
Even YOU are able to create, install and run a program, if I give you a very short crash-course.

Said program will be written in Shell script and will be executed from Linux Terminal (that is available as third-party application).
Listing of sample program in shell, called hello.sh
#### beginning of hello.sh file ####
echo "Hello World"
#### end of hello.sh file ####

There are some games, some utilities, such as Terminal Emulator mentioned in previous paragraph, there is ported CoolReader, modified version of FBReader ...

BusyBox provides several stripped-down Unix tools in a single executable. It runs in a variety of POSIX environments such as Linux, Android[5], FreeBSD[6] and other proprietary kernels, although many of the tools it provides are designed to work with interfaces provided by the Linux kernel. It is ideally suited to run in embedded devices. It has been self-dubbed "The Swiss Army Knife of Embedded Linux"
...

Are "we" able to install and run a linux program on one of these devices? Is that capability available to linux versed end users?

What program?

You can't run GUI linux applications that uses GTK,Qt and other libraries. You also can't run programs that uses ncurses. You only can run console applications (re-compilation for arm architecture is needed) and shell scripts.

But there are a lot of programs developed for the pocketbook by community.

thanks everyone for the input. when i was getting ready to ask this i was stuck on the idea that i really dont know linux. of course i had the answer all along i just needed a hand holding it seems. of course it would have to be something compiled for the device and not just a general "desktop" linux application

im thinking about the problem of better annotations for this and other linux based devices and came across a company that might be able to provide something. of course they need to have a good business case to go through the effort. my customer base is too small but the over all pocketbook base is probably large enough. ill have to see if they are still interested.

So I just managed to install poterm, I'm about to test some shell scripts, but I can't find the mentioned /mnt/ext1/applications.
Or is that the path to the sdcard?
if so, can I create custom dirs on he main memory also? Will it be lost with an update?
And do we have cron on the Pocketbook?

So I just managed to install poterm, I'm about to test some shell scripts, but I can't find the mentioned /mnt/ext1/applications.
Or is that the path to the sdcard?
if so, can I create custom dirs on he main memory also? Will it be lost with an update?
And do we have cron on the Pocketbook?

/mnt/ext1 is the path to the internal memory that you can write to. /mnt/ext2 is the SD card.

You can create directories in /mnt/ext1, /mnt/ext2, and /tmp. You cannot write to / and ebrmain because they are read-only. If you get root, you can write to /mnt/secure, and also to / and ebrmain if you re-mount them as read/write. Note that the getroot.app program no longer works with the latest firmware versions (but should work with 2.0.6).

Updates replace "/" and ebrmain entirely. They dd new filesystems right to each partition. So, any files written there previously are completely wiped out.

maybe I do it wrong in a way.
I run debian with KDE. When I mount it within the file manager it got mounted
/dev/sdX on /media/Pocketbook
Or do I have to mount manually with other options?

No. /mnt/ext1 and /mnt/ext2 are the mount points on the reader itself (what you would see when running poterm). From your desktop computer, the two would be mounted somewhere else. Anyway, the applications directory is on the internal RAM partition, and not on the SD card.